SMLE in 7.62x54R

[this thread started off about a 54R conversion, and morphed into a .45-70 build. -TRX]

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I think another project just crawled into the queue. Right now all my funds and spare time are taken up on the current project, so this one will have to wait...

I was rummaging in the shop the other day and found a 1944 Enfield action. The barrel has a hole drilled across the front of the breech, the bolt has gigantic rust pits, and it's missing most of the rest. I'd unscrewed the barrel, then written it off as junk. The barreled action has leaned against the wall since 1993, best as I can figure.

Looking it it, it appears the whole thing was glass beaded at one time. Despite the horrendous damage to the bolt, the action appears to be just fine. And the barrel is bright and clean, despite the hole drilled in it...

Add it all up, and I could probably find a shooter for about the same price... but I could set the barrel back a few threads, rent a 54R chambering reamer, and have an SMLE in 7.62x54R. 54R ammo is way cheaper than .303, and it would shoot the same ammo as my Nagant.

A friend was trying to persuade me to build it in 7.62x25 with a PPsh drum magazine. He was kidding... I think.

Hello TRX,
What a cool project !!!!
Set that barrel back and rechamber it to 7.62x54R Russian if enough meat exists. It could even be a Jungle Carbine with the flash hider muzzle and stock work, a Russo-British Jungle Carbine.

The pinned barrel chamber is typical of a British dewat or DP (drill purpose) rifle. The firing pin may be clipped off.

I had a 1945 model in the '80s, and got rid of it after determining the receiver was made out of cast iron. I was dressing a few rough spots with a file, and metal was coming off in the usual dark powder like iron does, instead of bright shavings like most steels.

This one is also a casting. It must be some pretty good stuff; I'd never heard of an SMLE failure, and I just spent some time googling as well. There are a lot of SMLEs out there around a century old, and a lot of them shot bunches of that hot Greek machine gun ammunition that was on sale everywhere in the '80s.

The cast iron part worries me because it's a rear locking lug action, and (apparently in the interest of removing weight) there's darned little metal connecting the barrel ring to the locking lugs. On the right side, there's even a slot that looks like a "don't do this" example out of any engineering textbook. The bolt looks like a pencil compared to anything bigger than a .22LR. Yet they appeared to be reliable in service, and even American commercial .303 ammunition is no joke.

Comparing a Remington 788 (a common commercial rear-locking action) and an SMLE, I get the urge to hide my eyes and make small whimpering noises.

As a bolt action the SMLE is quite unusual. Rear locking is unusual, of course. Since there are no forward locking lugs in the receiver, the lugs on the bolts cam into slots cut in the rear sidewalls. The closing cams are around 30 degrees, and about half again as long as the actual lug bearing area. Enfield really, *really* wanted you to be able to get off that next shot.

The bottom front edge of the left bolt lug rides an extraction ramp of about 30 degrees, perhaps double the width of the bolt mating surface. That's the main extraction force. The firing pin spring is quite stout, and probably provides sufficient extraction force all by itself.

The right outer locking face is, as I mentioned, just a cut in the sidewall, like some .22 or .410 bolt actions. The left side is machined into the side of the wall from the inside. I can see end mill cutter marks in there. It looks like you could reach in there with a quarter inch end mill for the basic recess, then a 3/8 or 1/2" keyseat cutter for the closing ramp.
That assumes they were actually cut; if the receiver is an investment casting, the whole cutout could be cast. Final machining could cut the right lug to match the cast left lug...

The bolt head slides through an internal reinforcing ring, like a '98 Mauser, sort of. Any extra strength couldn't hurt.

There's a big socket cast onto the back of the action, hanging down underneath at an angle, for mounting the stock. There's very little metal on the right side, no fillets or radii to prevent cracks... all the recoil goes through this offset joint. The lug under the barrel is just for mounting the forward wood.

Three 1/16" or so holes are drilled in the sidewall on the left side of the breech, approximately alongside the rim of a chambered cartridge. This makes a small slot, presumably to give gas from a ruptured case another escape path. The shape and position of the slot looks like another "don't do this" directly in the left-side load path.

("but it works", I keep repeating to myself...)

A strange thing is, if you put a .580" hole through a piece of 1-1/4" round bar, counterbored the end and cut threads with a boring bar or big tap, you could finish the rest of the machining on a mini-mill and have a tube receiver that would accept an Enfield barrel and bolt. Opening it up for the Enfield double-stack magazine would sacrifice a lot of metal... of course, you could start with a square bar.

If you wanted to build your own receiver, basing something off the SMLE would be WAY easier than trying to cut conventional raceways, though maybe no easier than some of the fat-bolt designs.

hmm sounds like a plausable build!
i have an ishipore enfield in 308
i wonder how hard that would be to swap to 7.62x54?
the cartriges are about the same size
but i wonder if the 303 enfield is large enuff to handle the 54?
icompared my 2 long ago and it seems the 308 is a bit beefier
looks like different recievers
itd be an interesting project
kep us posted

i wonder how hard that would be to swap to 7.62x54?
the cartriges are about the same size
but i wonder if the 303 enfield is large enuff to handle the 54?

I found several references to conversions online. Basically involves setting the barrel back a couple of threads, recutting the extractor, and running a 54R reamer in. Some people claimed minor bolt head mods were needed, others said it worked fine. Apparently there are no magazine problems.

Speaking of which, at least one person managed to mate a 30-round Bren mag to an Enfield. And there is at least one company out there converting them to 7.62x39, using 10 or 30 round AK mags.

Lots of comments from people who couldn't understand why someone would want to convert to 54R. Either they don't realize cheap import .303 is long gone, or the price difference between spam cans full of Commie 54R and commercially-loaded .303 is beneath their notice.

Hello TRX,
In WW-II the Australians and Kiwis converted a number (five thousand) early SMLE's to LMG's using an adapted 30 round (Bren) mag. This was the Chariton conversion, a 16.5 lb gas-operated gun.

I found several references to conversions online. Basically involves setting the barrel back a couple of threads, recutting the extractor, and running a 54R reamer in. Some people claimed minor bolt head mods were needed, others said it worked fine. Apparently there are no magazine problems.

Speaking of which, at least one person managed to mate a 30-round Bren mag to an Enfield. And there is at least one company out there converting them to 7.62x39, using 10 or 30 round AK mags.

Lots of comments from people who couldn't understand why someone would want to convert to 54R. Either they don't realize cheap import .303 is long gone, or the price difference between spam cans full of Commie 54R and commercially-loaded .303 is beneath their notice.

yes the 54r is way cheaper than the 303 and 308 military or commercial
im realy supprised there arent more 54r conversions but im guessing well be seing more due to the economy
can you post some of the conversion referances?
i would like to try one i have a sporterized mk3 id use as a donor-piss poor sporter but be a good candidate still solid

There was a company doing that about 20 years ago. Later it was determined that the pressure increase might not be worth the risk. The UK did test original receivers with 7.62x51 proof loads and had unacceptable receiver stretch after 6 proof loads. The UK 7.62x51 proof loads are not as hot as US military proof loads. The UK used a special heat treatment on the 7.62x51 Lee-Enfield receivers and figured that was good enough for factory military ammunition. Some 7.62x54R ammunition is fairly mild like the Polish ammo but some others like the Chinese ammo can be really hot.